The present invention relates to a device for a combustion chamber of a gas turbine for controlling the intake of gas into the combustion zone of the combustion chamber. The device comprises (includes, but is not limited to) a control element that is arranged outside the combustion chamber. This control element has a first means of covering at least a first inlet to the combustion zone and is displaceable in relation to the combustion chamber. There is also a means of supporting the control element connected to the cover means.
The term gas turbine relates to a unit which comprises at least one turbine and a compressor that is driven thereby, together with a combustion chamber. Gas turbines are used, for example, as engines for vehicles and aircraft, as prime movers for ships and in electricity-generating power stations.
The gas delivered to the combustion chamber by way of the inlet is usually air, but other gases are also conceivable.
One or more fuel distributors or fuel injectors are arranged in the combustion chamber. The term combustion zone relates to a section in proximity to, and at least substantially in front of the fuel distributor (s) in the longitudinal direction of the combustion chamber. The combustion zone is in turn usually divided up into a primary zone and a dilution zone in the direction away from the fuel distributor.
In order to be able to bring about combustion with low emissions, it is desirable to have the facility for controlling the temperature in the primary zone of the combustion chamber so that it lies within a certain range. This is achieved by using various types of control devices to control the air flow while it is being delivered to the primary zone and/or the dilution zone.
U.S. Pat. No. 4,944,149 describes a device for a combustion chamber for controlling the air intake to the dilution zone of the combustion chamber for the purpose of reducing NOx emissions. The device comprises a rotatable ring, which extends around the combustion chamber in the intended dilution zone thereof. The ring has a plurality of through-openings and the combustion chamber wall has correspondingly shaped openings. By bringing the ring openings over the openings in the combustion chamber wall, ducts are formed for the air from the outside to the inside of the combustion chamber.
A temperature sensor is provided for controlling the rotation of the ring. Due to the very high temperature around the combustion chamber, the constituent parts of the device are subject to great stress, which means that the device has a relatively short service life.